The present invention is related to a water proof press contact terminal and a method for forming a water proof press contact terminal for preventing rust of a core wire part of an electric wire which is press contacted to an electric wire press contact part of a terminal.
Conventionally, to press contact an exposed core wire part made of electrically conductive metal and a sheath part made of a synthetic resin of an insulating coated electric wire to a terminal made of electrically conductive metal, for instance, Patent Document 1 discloses that a core wire press contact part of a terminal is extended to a rear sheath in order to prevent water droplets from sticking to an exposed core wire part. A roof shaped covering part is integrally extended and formed in a front end of the core wire press contact part to cover an end of the exposed core wire part with the covering part and protect the core wire part.
Further, Patent Document 2 discloses that a U shaped folded part is integrally formed in a front base plate part of a core wire press contact part as a press contact terminal for an intermediate joint, but to improve a positioning property of an end of an exposed core wire part of an electric wire. The exposed core wire part is arranged inside the folded part, an exposed core wire part of other electric wire is arranged outside the folded part. The core wire press contact part is press contacted to the folded part to join both the electric wires together. However, the U shaped folded part in Patent Document 2 is formed in order not to waterproof.
FIG. 7 shows one form of a terminal with an electric wire as a reference in which an electric wire 53 is attached under pressure and connected to a usual press contact terminal 52. Reference numeral 54 designates a core wire press contact part. Reference numeral 55 designates a sheath press contact part. Reference numeral 56 designates a female type electric contact part to which a mate male terminal is inserted and connected.
A press contact operation of the terminal 52 and the electric wire 53 is carried out between an anvil (a lower mold) and a crimper (an upper mold) of a terminal press contact machine which is not shown in the drawing. Since after the press contact operation, a core wire 51 is exposed short in front and rear parts of the core wire press contact part 54, core wire exposed parts 51a and 51b need to be waterproofed. Especially, when a copper alloy is used for the press contact terminal 52 and aluminum is used for the core wire 51 of the electric wire 53 and water sticks to the terminal 52 and the core wire 51 made of dissimilar metals, a corrosion is liable to progress by an electrochemical reaction to increase an electric resistance due to the corrosion and deteriorate a current supply performance.
FIG. 8 shows one example of a stamped form of a transverse chain terminal 57 as a base material of the usual press contact terminal 52 as a reference. A base plate part 60 is arranged in one side end of a chain belt 58 through a connecting piece 59, one pair of sheath contact pressure pieces 55 protrude to both sides from a rear end of the base plate part 60 and one pair of core wire press contact pieces 54 protrude to both sides from an intermediate part of the base plate part 60. In a front part of the base plate part 60, the male or female type electric contact part 56 is arranged.
The press contact pieces 54 and 55 or the electric contact part 56 are respectively formed by a bending work by a press from the expanded states shown in FIG. 8 and the press contact pieces 54 and 55 are respectively raised upward. Press contact parts are formed respectively by the pairs of press contact pieces 54 and 55 and the base plate part 60 between them. In the chain belt 58, hole parts 61 are provided with which terminal feeding pawls of the terminal press contact machine not shown in the drawing are engaged. The chain belt 58 is cut from the connecting piece 59 and separated from the terminal 52 at the same time as the press contact of the electric wire 53 in the terminal press contact machine.
[Patent Document 1] JP-A-2010-55874
[Patent Document 2] JP-UM-A-5-45903